The invention relates to a method of and an apparatus for recording and/or reproducing a data packet transmitted in a television signal in time multiplex with the picture information.
The German patent application P 36 13 798.7 of 24-04-'86, hereby incorporated by reference, discloses a method of recording satellite television signals. In this method, the input signal is processed with the use of a memory in such a manner that two kinds of time gaps are obtained, the first of which occurs at line frequency, and the second of which occurs at field frequency. For this purpose, successive lines of the satellite television signal are cyclically supplied to n memory units of the memory for time expansion. The time-expanded signal is distributed over k channels. Synchronous pulses are formed in the gaps occurring at line frequency. The time-expanded signals are recorded by means of the oblique track method on k parallel tracks of a magnetic tape, while during the gaps that occur at field frequency, the head change-over takes place. The time-expanded signal is distributed over the k channels in such a manner that each channel contains alternately U and V components of the chrominance signal of the satellite television signal. If it is ensured that the reading processes associated with the individual channels begin and terminate at the same time, a drop-out compensation is possible during recording. In this case, the information disturbed as a result of a drop-out is replaced by an information from the other channel. Consequently, also in the case of a drop-out, a colored picture of half vertical resolution can be obtained.
Furthermore, it is already known, for example, from DE PS 3227373 to combine words consisting of binary signal elements to multi-bit sample values and to record signals stepped as quantizing signals after a digital-to-analog conversion by means of a video recorder. Summary of the Invention
The invention has for its object to provide a method of recording a data packet transmitted in a television signal in time multiplex with the picture information, which method permits of obtaining a drop-out compensation on the reproduction side.
The advantages of the invention reside in the fact that a drop-out compensation can be effected in a data packet recorded by means of the method according to the invention. This is essentially achieved by first separating the data packet from the television signal, then forming for each packet a plurality of redundant data packets delayed with respect to teach other by time. Each of the redundant packets are then multiplexed in time with respective data packets and subjected to a multi-level coding process. As a result, it is achieved inter alia that in spite of the redundance introduced it is not necessary to make available an additional band width for recording. The multi-level informations obtained thereby are processed so that the informations associated with a line and present in multiple are recorded with time offset on different channels or oblique tracks of a record carrier. During the reproduction of a data packet thus recorded, in the case of a drop-out, the information recorded each time in the other track can be evaluated instead of the disturbed information. Brief Description of the Drawings
Further favorable properties appear from an embodiment, which will be described more fully hereinafter with reference to FIGS. 1 to 6.